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Articles 751 - 780 of 1239

Full-Text Articles in Animal Sciences

Effects Of Gregariousness, Conspicuousness, And Novelty On Blue Jay (Cyanocitta Cristata) Learned Avoidance And Stimulus Generalization Of Unpalatable Prey, Joyce M. Dykema Apr 2008

Effects Of Gregariousness, Conspicuousness, And Novelty On Blue Jay (Cyanocitta Cristata) Learned Avoidance And Stimulus Generalization Of Unpalatable Prey, Joyce M. Dykema

Avian Cognition Papers

I examined a variety of factors hypothesized to be important in the evolution and maintenance of aposematism. Aposematism occurs when prey individuals advertise their toxic or otherwise aversive nature to potential predators via evolved conspicuous signals. I conducted three experiments in which blue jays (Cyanocitta cristata) were allowed to search a printed grayscale pixilated background for grayscale pixilated moths in an open room. I manipulated moth appearance and food reward, and recorded jay predation on the varying moth stimuli. In my first experiment, I repeated Alatalo & Mappes’ (1996) study examining the effects of prey gregariousness, or grouping, …

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Aerial Census Techniques For Whooping Cranes On The Texas Coast, Thomas V. Stehn, Thomas E. Taylor Jan 2008

Aerial Census Techniques For Whooping Cranes On The Texas Coast, Thomas V. Stehn, Thomas E. Taylor

Proceedings of the North American Crane Workshop

The U.S. Fish and Wildlife Service, using aerial surveys, regularly monitors the whooping crane (Grus americana) population wintering along the Texas coast. These regular census flights began in 1950 and have produced a long-term data set on the growth of a small population of endangered birds. This paper describes the specific methodology used by the authors during census flights.

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Extra-Pair Paternity In Sandhill Cranes, Matthew A. Hayes, Hugh B. Britten, Jeb A. Barzen Jan 2008

Extra-Pair Paternity In Sandhill Cranes, Matthew A. Hayes, Hugh B. Britten, Jeb A. Barzen

Proceedings of the North American Crane Workshop

Although cranes are known for “life-long” pair bonds, exceptions to this rule have been observed (i.e. divorcing pairs and individuals re-pairing following the death of a mate). With advancements in genetic techniques, another form of infidelity has been observed: extra-pair paternity (EPP; producing young with a bird while being socially paired to another mate) has been documented in many avian species. Is this true for cranes as well? Sandhill cranes (Grus canadensis) from a dense breeding population in southcentral Wisconsin were tested for EPP using 6 microsatellite DNA markers. The frequency of EPP ranged between 4.4% (2 of 45 chicks) …

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Mate Fidelity In A Dense Breeding Population Of Sandhill Cranes, Matthew A. Hayes, Jeb A. Barzen, Hugh B. Britten Jan 2008

Mate Fidelity In A Dense Breeding Population Of Sandhill Cranes, Matthew A. Hayes, Jeb A. Barzen, Hugh B. Britten

Proceedings of the North American Crane Workshop

The objective of this study was to investigate mate switches observed in a dense breeding population of banded Sandhill Cranes (Grus canadensis). Over a 14-year period, 50 of 70 breeding pairs switched mates (71%), with 45 pairs switching permanently (64%). Mean mate retention between years was 83%, with an average pair bond lasting 5.7 years (range 1-13 years). Most permanent switches occurred following the death or disappearance of a mate, and overall permanent divorce (19%; 13 of 70 pairs) and annual divorce rates (6%) were low. Territory retention following mate switches was high. Males and females did not …

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The Whooping Crane In Mexico: Past, Present, And Future?, Michael S. Putnam, Ruth Partida Lara, Suix Diaz Gomez, Anne E. Lacy Jan 2008

The Whooping Crane In Mexico: Past, Present, And Future?, Michael S. Putnam, Ruth Partida Lara, Suix Diaz Gomez, Anne E. Lacy

Proceedings of the North American Crane Workshop

We reviewed ornithological, historic, anthropological, and archaeological records for evidence of whooping cranes (Grus americana) in Mexico. Records of whooping cranes in Mexico span 88 years (1863-1951) and cluster in 3 areas. Wintering records come from the northern highlands (Durango, and possibly Chihuahua), the central highlands (Guanajuato, Jalisco), and northeastern Tamaulipas, where the bird was also found in summer and might have bred. Later records (1970’s and 1980’s) of whooping cranes in the northern highlands are from individual birds released into the experimental migratory population that formerly migrated from Idaho to New Mexico, USA. Many of the wetlands …

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The Natural History And Distribution Of The Mountain Earthsnake (Virginia Valeriae Pulchra) In West Virginia, Daniel Ware Jan 2008

The Natural History And Distribution Of The Mountain Earthsnake (Virginia Valeriae Pulchra) In West Virginia, Daniel Ware

Theses, Dissertations and Capstones

The Mountain Earthsnake, Virginia valeriae pulchra, has received little attention in the literature to date. It is imperiled in West Virginia with only 6 to 20 populations known throughout the Allegheny Mountain and Ridge and Valley Physiographic provinces. Eighty snakes were collected during the 2006 and 2007 summers. Typical habitat is open fields with short grass, flat to moderate slopes that have scattered fine sandstone rocks near a source of water and forest edge. Fine sandstone rocks were the primary cover objects used. Snakes were sexually dimorphic with males having longer tails expressed as a percent of total body lengths …

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Precision Of Descriptors For Percent Marrow Fat Content For Whitetailed Deer, Odocoileus Viriginianus, L. David Mech Jan 2008

Precision Of Descriptors For Percent Marrow Fat Content For Whitetailed Deer, Odocoileus Viriginianus, L. David Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Based on 168 records of both verbal descriptors of White-tailed Deer (Odocoileus virginianus) femur-marrow fat and percentage of fat measured later, “gelatinous” served well to distinguish fat < 46% from higher percentages. “Waxy” distinguished fat > 56%.

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Elk Calf Survival And Mortality Following Wolf Restoration To Yellowstone National Park La Supervivencia Y La Mortalidad De Las Crı´As De Wapiti Tras La Restauracio´ N Del Lobo Al Parque Nacional De Yellowstone La Survie Et La Mortalite´ Des Faons De Wapitis Qui A Suivi La Re´Introduction Du Loup Au Parc De Yellowstone, S. M. Barber-Meyer, L. David Mech, P. J. White Jan 2008

Elk Calf Survival And Mortality Following Wolf Restoration To Yellowstone National Park La Supervivencia Y La Mortalidad De Las Crı´As De Wapiti Tras La Restauracio´ N Del Lobo Al Parque Nacional De Yellowstone La Survie Et La Mortalite´ Des Faons De Wapitis Qui A Suivi La Re´Introduction Du Loup Au Parc De Yellowstone, S. M. Barber-Meyer, L. David Mech, P. J. White

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

We conducted a 3-year study (May 2003–Apr 2006) of mortality of northern Yellowstone elk (Cervus elaphus) calves to determine the cause for the recruitment decline (i.e., 33 calves to 13 calves/100 adult F) following the restoration of wolves (Canis lupus). We captured, fit with radiotransmitters, and evaluated blood characteristics and disease antibody seroprevalence in 151 calves ≤ 6 days old (68M:83F). Concentrations (x, SE) of potential condition indicators were as follows: thyroxine (T4; 13.8 µg/dL, 0.43), serum urea nitrogen (SUN; 17.4 mg/dL, 0.57), c-glutamyltransferase (GGT; 66.4 IU/L, 4.36), gamma globulins (GG; 1.5 g/dL, 0.07), and insulin-like …

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Factors Influencing Predation On Juvenile Ungulates And Natural Selection Implications, S. M. Barber-Meyer, L. D. Mech Jan 2008

Factors Influencing Predation On Juvenile Ungulates And Natural Selection Implications, S. M. Barber-Meyer, L. D. Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Juvenile ungulates are generally more vulnerable to predation than are adult ungulates other than senescent individuals, not only because of their relative youth, fragility, and inexperience, but also because of congenital factors. Linnell et al.’s (Wildl. Biol. 1: 209-223) extensive review of predation on juvenile ungulates concluded that research was needed to determine the predisposition of these juveniles to predation. Since then, various characteristics that potentially predispose juvenile ungulates have emerged including blood characteristics, morphometric and other condition factors, and other factors such as birth period, the mother’s experience, and spatial and habitat aspects. To the extent that any of …

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Variation In Surrounding Forest Habitat Influences The Initial Orientation Of Juvenile Amphibians Emigrating From Breeding Ponds, Leroy J. Walston, Stephen J. Mullin Jan 2008

Variation In Surrounding Forest Habitat Influences The Initial Orientation Of Juvenile Amphibians Emigrating From Breeding Ponds, Leroy J. Walston, Stephen J. Mullin

Faculty Research & Creative Activity

No abstract provided.

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Trends In Habitat And Population Of Florida Sandhill Cranes, Stephen A. Nesbitt, James L. Hatchitt Jan 2008

Trends In Habitat And Population Of Florida Sandhill Cranes, Stephen A. Nesbitt, James L. Hatchitt

Proceedings of the North American Crane Workshop

To map the areas of potential occupied habitat for Florida sandhill cranes (Grus canadensis pratensis) in Florida we used known habitat requirements and confirmed locations of occurrence in combination with a Geographic Information System. Using the map of potential habitat resulting from this process, we calculated the changes in the amount and distribution of crane habitat in Florida in 10-year increments since 1974. Based on annual home range sizes, age structure, and average flock size, we estimated the statewide population of Florida sandhill cranes in 2003 to be 4,594 individuals. Considering the area of crane habitat lost since …

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Proceedings Of The Tenth North American Crane Workshop: Cover, Preface, Contents Jan 2008

Proceedings Of The Tenth North American Crane Workshop: Cover, Preface, Contents

Proceedings of the North American Crane Workshop

Every 3 years (or thereabouts), the North American Crane Working Group holds a workshop for the exchange of information regarding efforts to conserve and better understand America’s two cranes. The papers herein, with a few exceptions, were presented in Zacatecas City, Zacatecas, Mexico 7-10 February 2006 at the Tenth North American Crane Workshop. When preparing for a trip to Mexico in February, visions of sunny beaches come first to mind. However the city of Zacatecas is over 8,000 feet above sea level, so nights were often chilly and the altitudinal changes took a while for us flatlanders to adjust to. …

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A Wasting Syndrome In Released Whooping Cranes In Florida Associated With Infectious Bursal Disease Titers, Marilyn G. Spalding, Holly S. Sellers, Barry K. Hartup, Glenn H. Olsen Jan 2008

A Wasting Syndrome In Released Whooping Cranes In Florida Associated With Infectious Bursal Disease Titers, Marilyn G. Spalding, Holly S. Sellers, Barry K. Hartup, Glenn H. Olsen

Proceedings of the North American Crane Workshop

Whooping cranes (Grus americana) have been reintroduced into central Florida beginning in 1993 until the present. Bobcat predation of otherwise healthy cranes in good nutritional condition was the most common cause of mortality. However, release cohorts in the years 1997-1998 (14/22 died) and 2001-2002 (14/27 died, 5/27 clinical illness) experienced unusually high morbidity and mortality. Positive serum neutralizing titers for infectious bursal disease virus (IBDV) were identified following the 2001 event, and an epidemiological study of released birds and the captive source flocks was initiated. Serotype 1 (Lukert and Variant A) tests were mostly negative. Serotype 2 testing …

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New Hunter Education Strategies To Protect Whooping Cranes In Texas And Kansas, Lee Ann Johnson Linam, Helen M. Hands, Jay Roberson Jan 2008

New Hunter Education Strategies To Protect Whooping Cranes In Texas And Kansas, Lee Ann Johnson Linam, Helen M. Hands, Jay Roberson

Proceedings of the North American Crane Workshop

The decline of the whooping crane (Grus americana) has often been attributed primarily to loss of habitat and overharvest. Although hunting of whooping cranes is now prohibited, shootings sometimes occur. Recent incidences have prompted the Texas Parks and Wildlife Department (Texas) and the Kansas Department of Wildlife and Parks (Kansas) to develop new strategies that increase hunter recognition of legal game species and awareness of endangered species concerns. Both agencies have produced or updated publications for goose and sandhill crane (Grus canadensis) hunters. Texas has developed video news releases for the general public and a video/DVD …

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The Cuban Sandhill Crane As Umbrella Species: Relationship With Plant Diversity In Threatened White Sand Savannahs, Duniet Marrero Garcia, Jose A. Osorio, Xiomara Galvez Aguilera, Felipe Chavez-Ramirez Jan 2008

The Cuban Sandhill Crane As Umbrella Species: Relationship With Plant Diversity In Threatened White Sand Savannahs, Duniet Marrero Garcia, Jose A. Osorio, Xiomara Galvez Aguilera, Felipe Chavez-Ramirez

Proceedings of the North American Crane Workshop

This project describes relationships between the Cuban sandhill crane (Grus canadensis nesiotes) distribution and habitat use and plant diversity in white sand savannahs, a threatened ecosystem in Cuba. Data are based on habitat use and selection of 10 radio-tagged sandhill cranes in the Los Indios Ecological reserve, Isle of Youth. We used Arcview and satellite imagery to map broad vegetation categories. Within the general Pine-Palm savannahs specific plant communities were characterized using species composition and dominant plant life forms. Habitat types most used by cranes for feeding and nesting were also those with highest plant species richness and …

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Temporal Dynamics And Flock Characteristics Of Sandhill Cranes In The Platte River Valley, Nebraska, Felipe Chavez-Ramirez Jan 2008

Temporal Dynamics And Flock Characteristics Of Sandhill Cranes In The Platte River Valley, Nebraska, Felipe Chavez-Ramirez

Proceedings of the North American Crane Workshop

I gathered information on crane flocks in the Platte River Valley during spring staging of 2002-2004. The objective of
this work was to evaluate hypotheses regarding flock size and formation using sandhill crane (Grus canadensis) flocks observed in
the Platte River Valley. Specifically, I wanted to: (a) evaluate the effect of period of migration, geographical location, and habitat
type on flock size, and (b) evaluate predictions regarding ecological theories of flock formation and behavior based on concentrated
resources, accessibility, social facilitation, and potential predation response. Flock size overall was influenced negatively by period
of migration (P < 0.001) and positively by geographical location (P < 0.01). Total crane abundance (55%) of flocks were located
in corn fields, but …

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Population Status, Hunting Regulations, And Harvests Of The Rocky Mountain Population Of Greater Sandhill Cranes, 1981–2005, Kammie L. Kruse, David E. Sharp, James A. Dubovsky Jan 2008

Population Status, Hunting Regulations, And Harvests Of The Rocky Mountain Population Of Greater Sandhill Cranes, 1981–2005, Kammie L. Kruse, David E. Sharp, James A. Dubovsky

Proceedings of the North American Crane Workshop

The Rocky Mountain Population (RMP) of greater sandhill cranes (Grus canadensis tabida) was not hunted in the U.S. from 1916 until 1981, when Arizona initiated the first modern-day season. Hunting programs in the U.S. were subsequently expanded to 6 states for the RMP and have been guided by a cooperative flyway management plan, including a harvest strategy, which has been periodically updated and endorsed by the Central and Pacific Flyway Councils. From a management perspective, 3 population parameters have been identified to monitor the status and health of this population: harvest, recruitment, and population size. The number of …

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Serological Survey For Infectious Bursal Disease Virus Exposure In Captive Cranes, Barry K. Hartup, Holly S. Sellers Jan 2008

Serological Survey For Infectious Bursal Disease Virus Exposure In Captive Cranes, Barry K. Hartup, Holly S. Sellers

Proceedings of the North American Crane Workshop

Between September 2001 and March 2002, unusually high morbidity and mortality was observed during releases of endangered, captive-reared whooping cranes (Grus americana) in central Florida. An ongoing epidemiological investigation has implicated infectious bursal disease virus (IBDV; Family Birnaviridae) as the likely etiological agent (Spalding et al. 2008). The source of this virus remains unknown. A previous serological survey showed positive antibody titers to IBDV serotype 2 were present in small numbers of juvenile and adult whooping cranes at the International Crane Foundation (ICF), Baraboo, Wisconsin and the Patuxent Wildlife Research Center, Laurel, Maryland between 1995 and 2003 (Hartup et al. …

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Do We Need Such Rare Birds?, Stephen A. Nesbitt Jan 2008

Do We Need Such Rare Birds?, Stephen A. Nesbitt

Proceedings of the North American Crane Workshop

Gruidae is one of the oldest bird families; the genus Grus dates back at least 9 million years. Though they may have been around a long time, it is unlikely that cranes were ever among the most abundant of birds. Several of the 15 crane species occur today in such low numbers that they are considered in danger of becoming extinct. It has been posited that at the time of European colonization of North America whooping cranes may have numbered 10,000 individuals, so whooping cranes have likely always been rare birds. Rare has often been used as a synonym for …

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Winter Habitat Selection By A Reintroduced Population Of Migratory Whooping Cranes: Emerging Patterns And Implications For The Future, Lara E. A. Fondow Jan 2008

Winter Habitat Selection By A Reintroduced Population Of Migratory Whooping Cranes: Emerging Patterns And Implications For The Future, Lara E. A. Fondow

Proceedings of the North American Crane Workshop

In an effort to model the reintroduced eastern migratory population of whooping cranes (Grus americana) after the remaining wild whooping crane population, biologists selected the salt marshes of Chassahowitzka National Wildlife Refuge (NWR), Florida as the winter release site for ultra-light led juvenile cranes due to its similarities to Aransas NWR, Texas. Releases began in the fall of 2001, and the 3 subsequent winter seasons have afforded the opportunity to observe whether habitat selection by these whooping cranes would be influenced by the pre-selection of salt marsh. Intensive monitoring efforts each winter have revealed a dominant early-winter pattern. …

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Surveillance For West Nile Virus At The International Crane Foundation 2000–2004, Barry K. Hartup Jan 2008

Surveillance For West Nile Virus At The International Crane Foundation 2000–2004, Barry K. Hartup

Proceedings of the North American Crane Workshop

Between 2000 and 2004, serum samples collected annually from captive cranes at the International Crane Foundation (ICF) were analyzed for the presence of West Nile virus (WNV) antibodies using a plaque reduction neutralization test. Eighteen individual cranes representing 8 species were identified with positive titers (geometric mean = 188, range 40 – 1280, n = 29). Whooping cranes (Grus americana) represented the largest proportion of seropositive individuals (33%). Flock seroprevalence increased rapidly in 2003 and 2004 to a peak of 10%, representing a four-fold increase following index cases in 2000. None of the seropositive cranes, however, showed clinical signs consistent …

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Current Status Of Nonmigratory Whooping Cranes In Florida, Martin J. Folk, Stephen A. Nesbitt, Jeannette M. Parker, Marilyn G. Spalding, Stephen B. Baynes, Kristen L. Candelora Jan 2008

Current Status Of Nonmigratory Whooping Cranes In Florida, Martin J. Folk, Stephen A. Nesbitt, Jeannette M. Parker, Marilyn G. Spalding, Stephen B. Baynes, Kristen L. Candelora

Proceedings of the North American Crane Workshop

Two hundred eighty-nine nonmigratory whooping cranes (Grus americana) were released in Central Florida from 1993-2005. As of January 2006, we had monitored 50 birds (16 pairs) but suspect 10 others had also survived, for a population estimate of 60 birds. The sex ratio for monitored birds was 1:1. From 47 nest attempts (1999-2005), only 4 chicks have fledged and survived to independence. Efforts are underway to determine why recruitment has been lower than expected. Other challenges for the project have included birds colliding with power lines, dispersing beyond their normal range (beyond Florida), forming pair bonds with Florida sandhill cranes …

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Is The Annual March Survey Of The Midcontinental Sandhill Crane Population Appropriately Timed To Reliably Estimate Population Size?, Gary L. Krapu, David A. Brandt Jan 2008

Is The Annual March Survey Of The Midcontinental Sandhill Crane Population Appropriately Timed To Reliably Estimate Population Size?, Gary L. Krapu, David A. Brandt

Proceedings of the North American Crane Workshop

The U.S. Fish and Wildlife Service relies on an annual aerial photo-corrected survey conducted on the fourth Tuesday of March each year in the Central Platte River Valley (CPRV) and North Platte River Valley (NPRV) of Nebraska to estimate size of the midcontinental population (MCP) of sandhill cranes (Grus canadensis) to help guide population management. Wide unaccounted for annual fluctuations in survey counts over the past 25 years have raised concerns that many cranes either have left the Platte before the survey, have not yet arrived, or over fly the Platte entirely in some years. As a result, …

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Survival And Sources Of Mortality In Florida Sandhill Crane Chicks: Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding Jan 2008

Survival And Sources Of Mortality In Florida Sandhill Crane Chicks: Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding

Proceedings of the North American Crane Workshop

Forty-five pairs of Florida sandhill cranes (Grus canadensis pratensis) were monitored during the nesting seasons from 1996 through 1999. Thirty-eight chicks were produced from 25 successful nests. Twenty-one of these survived to fledging age. Predation was the source of most (81%) of the mortality for which a cause was determined. Mammals were the primary predator. Average age at time of mortality was 27.2 days for the 17 chicks lost.

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Interaction Of Young Florida Sandhill Cranes With Their Parents, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert Jan 2008

Interaction Of Young Florida Sandhill Cranes With Their Parents, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert

Proceedings of the North American Crane Workshop

We studied the interactions of 46 Florida sandhill crane (Grus canadensis pratensis) chicks and their parents from hatching until the chicks left the family group. Our goal was to see if young remained closer to one parent than the other and if the distance between a chick and its parents increased as the young approached the age of independence. Using a population of individually marked adult pairs, we ranked the distance to and gender of the nearest parent during 233 30-minute observation periods. Between hatching and 180 days of age, chicks showed a greater tendency to be nearer …

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Infectious Bursal Disease In Wild Populations Of Turkeys And Sandhill Cranes: Preliminary Findings, Kristen L. Candelora, Marilyn G. Spalding, Stephen A. Nesbitt, Holly S. Sellers, Jeremy Olson, Larry Perrin, Jeannette Parker Jan 2008

Infectious Bursal Disease In Wild Populations Of Turkeys And Sandhill Cranes: Preliminary Findings, Kristen L. Candelora, Marilyn G. Spalding, Stephen A. Nesbitt, Holly S. Sellers, Jeremy Olson, Larry Perrin, Jeannette Parker

Proceedings of the North American Crane Workshop

Captive-reared whooping cranes (Grus americana) released into Florida for the resident reintroduction project experienced unusually high mortality and morbidity during the 1997-1998 and 2001-2002 release seasons (Spalding et al. 2008). Infectious bursal disease virus (IBDV) serotype 2 is currently under investigation as the factor that precipitated the mortality events. A small percentage of whooping cranes have been exposed to IBDV in the captive setting. However, many more are being exposed postrelease, and prevalence of exposure seems to increase with age or length of time the birds are in the wild in Florida (Spalding et al. 2008). The goals …

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Reduction Of Crop Depredations By Cranes At Daursky State Biosphere Reserve, Siberia, Oleg A. Goroshko, John E. Cornely, Stephen H. Bouffard Jan 2008

Reduction Of Crop Depredations By Cranes At Daursky State Biosphere Reserve, Siberia, Oleg A. Goroshko, John E. Cornely, Stephen H. Bouffard

Proceedings of the North American Crane Workshop

The Daursky State Biosphere Reserve (SBR) in southern Siberia includes the Torey Lakes, the largest lakes in the Trans-Baikal region. The Torey Lakes support tens of thousands of breeding waterbirds and about a million waterbirds during migration. Peak numbers of birds staging during fall coincide with grain harvest. Crop fields around the Torey Lakes attract 50,000 to 70,000 waterbirds, primarily cranes with lesser numbers of waterfowl, causing significant crop damage in fields near Daursky SBR. Investigations of the problem have been ongoing since 1992. Field consultation by Cornely and Bouffard in 2001 resulted in recommendations to reduce depredations. The consultation …

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Reproductive Health Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt Jan 2008

Reproductive Health Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt

Proceedings of the North American Crane Workshop

We examined the reproductive parameters of the introduced non-migratory flock of whooping cranes in Florida. Of 289 cranes introduced, 67 males and 65 females survived at least 3 years. The first behavioral pairs appeared in 1995, and eggs were first laid in 1999. In total, eggs were laid in 47 nests, 17 chicks hatched, and 4 young fledged by 2005. Severe drought conditions through 2001 were thought to be the reason for low reproductive nest success. In 2003 nesting conditions improved and 71% of nests with eggs, hatched chicks. During the next 2 years, with continued wet conditions, the proportion …

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Distribution And Dispersion Patterns Of Sandhill Crane Flocks In The Platte River Valley, Brian Lorenz, Felipe Chavez-Ramirez Jan 2008

Distribution And Dispersion Patterns Of Sandhill Crane Flocks In The Platte River Valley, Brian Lorenz, Felipe Chavez-Ramirez

Proceedings of the North American Crane Workshop

We evaluated sandhill crane (Grus canadensis) flock distribution and dispersion patterns along the Platte River Valley, Nebraska, in 2002-2003. The objectives were to: (a) determine the overall distribution and relationship between roosting and foraging flock numbers by bridge segments, (b) evaluate flocking characteristics in relation to abundance of cranes in different bridge segments and total abundance, and (c) correlate dispersion patterns and habitat use to period of migration, roost locations, and habitat types. Preliminary predictions included: foraging flock dispersions would be correlated with roost locations; greater numbers and larger flock sizes will be present in bridge segments with …

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Responses Of Nesting Sandhill Cranes To Research Activities And Effects On Nest Survival, Jane E. Austin, Deborah A. Buhl Jan 2008

Responses Of Nesting Sandhill Cranes To Research Activities And Effects On Nest Survival, Jane E. Austin, Deborah A. Buhl

Proceedings of the North American Crane Workshop

We examined the response of nesting greater sandhill cranes (Grus canadensis tabida) to research-related activities at Grays Lake, Idaho, during 1997–2000. Data were collected on >500 crane nests from 53 fields that were exposed to variable levels of research activity, from fields subjected to only periodic searches for and monitoring of crane nests (crane-only fields) to fields subjected to periodic searches for and monitoring of all waterbird nests as well as breeding bird surveys, nocturnal amphibian surveys, and other research-related activities (multi-use fields). For each nest, we calculated the visit rate to the field during the period the …

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